Hens that started laying eggs too early and are underweight are likely to develop a disease called vent prolapse.
Vent prolapse in chickens, also known as prolapsed oviduct, blow-out, cloacal prolapse or pickout, is a condition in which the lower part of a hen’s oviduct turns inside out and protrudes through the vent. Prolapse is a very serious condition that is treatable if caught early, but is likely to recur.
This disease can also be caused by laying an egg that is too large, obesity (for older chickens), calcium deficiency and holding droppings for a long period of time (causing stress and stretching of the cloaca).
Here are some of the things you need to do when dealing with this disease:
Separate the sick chicken from the flock
Clean protruding tissue well
Apply hemorrhoid ointment (without pain killer) internally and externally
Provide vitamins and electrolytes or liquid calcium to restore the ability of the uterus muscle to contract properly
Consider administering antibiotics if tissue is compromised by pecking or is especially dirty
As it could recur, monitor the chicken properly over its lifetime
Also, keep the hen in a darkened crate for at least 24 hours to discourage egg-laying, which could exacerbate the condition.
Culling is usually recommended to chickens with prolapse in large poultry operations, but not in the backyard since the diseases is manageable. As long as the status of the chicken’s condition is monitored, culling is not necessary. The biggest danger to a chicken with prolapse is when other chickens pick on the reddened area. Repeated picking can result in the chicken’s oviduct and/or intestines being pulled out, resulting to death from cannibalism.